Alarm system for a crystal growing furnace
US5063518A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 16, 1989 |
| Grant date | Nov 5, 1991 |
| Priority date | — |
| Expiry date | Nov 16, 2009 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG05D23/22
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
The present invention monitors thermocouple data from a semiconductor furnace. The data is checked against a first set of profiles which mimic an intended operational temperature profile for the furnace. If the temperature measured in any zone of the furnace falls outside a first set of maximum and minimum limits fixed by the mimicking profiles, a warning is generated thereby giving operational personnel an opportunity to correct the condition. If the condition remains unchecked and further deviation occurs, a second condition is reached as defined by a corresponding second set of mimicking maximum and minimum profiles. This condition is established as a serious condition which will cause a microprocessor to terminate power supply to the furnace. Otherwise, the quality of the grown crystal would be jeopardized; or sufficiently excessive power would be delivered to the furnace so as to cause its damage or destruction.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.